Kefir is a product of fermentation of milk by kefir grains. Kefir grain is an agglomerate of various microorganisms of lactic acid bacteria, acetic acid bacteria and yeasts in a polysaccharide/protein matrix, which produces by some species of grain. Matrix protects grain (microbiota) from dissolution and invading of other species. The structure and composition of kefir grain is favorable for symbiotic relations of these different species.
Kefir is manufactured by industry in big amounts and sold on a large distance from the manufacturing site. Time between commercial manufacturing and consumption can be 2-3 months if stored at low temperatures and contains artificial substances like pectin. During the period of storage and transportation acidity of product increases and number of live probiotic cells significantly decreases. Storage and transportation always needs low temperature to prevent deterioration of product. Artificial additives like pectin are added to commercial kefir. These disadvantages of big commercial manufacturing decrease quality of kefir. Decreased quality of commercial kefir creates a need to produce fresh natural kefir at home.
Currently used process of homemade producing of kefir contains several time-consuming steps: adding milk to kefir grains, incubating around 24+/−4 hours at room temperature, separating grains from fresh kefir by plastic strainer and wooden spatula, collecting of ready kefir in separate jar, washing kefir grains in order to use them again in new cycle and cleaning all used utensils and working space. The process of separation through strainer significantly damages relatively soft kefir grains. Thus currently used method of homemade kefir production is not really simple, need training and experience and relatively time-consuming.